JPMorgan’s relationship with Bitcoin XBT came into question over the weekend when the financial blog Zerohedge asked why the bank was involved with the trading after CEO Jamie Dimon called bitcoin a fraud and said he would fire anyone at the bank who trades it.

Bitcoin is a digital currency that enables individuals to transfer value to each other and pay for goods and services outside of the regulated financial system.

Because it is not backed by any government and has been tied to crimes, including money laundering, hacking and drug trafficking, most financial institutions have stayed away from dealing inbitcoin.

Dimon captured that sentiment in his comments last week. “If we have a trader that trades bitcoin, I would fire them in a second, for two reasons: It is against our rules and they are stupid, and both are dangerous,” he said at an investor conference.

Even so, major financial firms including JPMorgan have invested in a technology called blockchain that underpins bitcoin transactions in hopes that it can be used for other purposes, such as settling ordinary trades.

Bitcoin prices fell last week to nearly $3,000 from $4,200 after Dimon spoke and China reportedly cracked down on crypto currency exchanges. But bitcoin rebounded with the new week, trading on the Bitstamp exchange at $4,025 on Monday.

Along with JPMorgan, more than a dozen banks, including Morgan Stanley, Goldman Sachs Group Inc and Credit Suisse Group AG, have acted as brokers for buying and selling Bitcoin XBT on Nasdaq’s Stockholm-based exchange, according to Swedish online bank Nordnet AB.